Applied Physics and Mathematics Annotation << Back HOW DO ELECTRIC AND MAGNETIC FIELDS MOVE? V.A. LEUS In nature, there are two fundamentally different types of motion of the electric and magnetic fields: dynamic and kinematic. A typical manifestation of the first type of motion takes place in a plane harmonic EM-wave. For already more than a century the question about the ratio of the phases of the electric and magnetic fields, oscillating in such a wave, remains open. From time to time in this regard, fierce disputes arise. The point is that far from any phase difference turns out to be compatible with the full system of Maxwellian equations. Maxwell’s classical theory as applied to such a wave leads to the conclusion that the electric and magnetic vectors in it oscillate harmoniously with zero phase shift. In the framework of this theory, a rigorous mathematical proof is given. Keywords: Electromagnetic wave, transverse oscillations in phase, longitudinal immobility of field vectors, electrokinematics, magneto-kinematics. DOI: 10.25791/pfim.04.2022.1235 Pp. 14-16.